Relaying for pair-wise information exchange

In the two-way relay channel, two sources exchange information with help from a relay. We study a more general relay network with additional pairs of sources that perform pair-wise information exchange. We obtain achievable rate regions for amplify-and-forward and decode-and-forward (DF) relaying schemes based on both Gaussian codes and lattice codes, assuming a two-phase protocol. The lattice-code-based DF scheme is near optimal, in that the achievable rate region lies within one bit of the capacity region for two pairs of information exchange.